diff -r 66b1a7c42d94 -r 1f9362e769c1 src/HOL/UNITY/SubstAx.thy
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/HOL/UNITY/SubstAx.thy	Fri Apr 03 12:34:33 1998 +0200
@@ -0,0 +1,19 @@
+(*  Title:      HOL/UNITY/SubstAx
+    ID:         $Id$
+    Author:     Lawrence C Paulson, Cambridge University Computer Laboratory
+    Copyright   1998  University of Cambridge
+
+My treatment of the Substitution Axiom -- not as an axiom!
+*)
+
+SubstAx = WFair +
+
+constdefs
+
+   LeadsTo :: "['a set, ('a * 'a)set set, 'a set, 'a set] => bool"
+    "LeadsTo Init Acts A B ==
+     leadsTo Acts (reachable Init Acts Int A)
+                  (reachable Init Acts Int B)"
+
+
+end